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2026 Updated Comorbidity Subgroups and Interactions

    In the CY 2026 Home Health Prospective Payment Final Rule, CMS finalized updates to the Patient-Driven Groupings Model (PDGM) that recalibrate how comorbid conditions influence payment adjustments. These updates reflect CMS’s ongoing effort to better align Medicare payments with actual patient care needs using the most recent utilization data.

    CMS updated the PDGM comorbidity adjustment subgroups using 2024 home health claims and OASIS data. The changes are intended to more accurately capture real-world resource utilization patterns for patients with multiple conditions.

    What Changed in the Comorbidity Adjustment Subgroups

    • Low Comorbidity Adjustment Subgroups
      • The number of low comorbidity adjustment subgroups was reduced to 20, down from 22 in CY 2025. The changes include:
        • Added 3 low comorbidity subgroups:
          • Heart 5
          • Musculoskeletal 1
          • Neoplasm 6
        • Removed 5 current low comorbidity subgroups:
          • Circulatory 7
          • Endocrine 3
          • Neoplasm 1
          • Neurological 11
          • Neurological 12
      • This reflects CMS’s refinement of which diagnoses continue to meet the threshold for low comorbidity payment adjustments based on updated utilization patterns.
    • High Comorbidity Subgroup Interaction
      • The number of high comorbidity subgroup interactions increased to 98 in CY 2026 (up from 94 in CY 2025). This includes the addition of 44 new interactions eligible for high comorbidity adjustments, while 40 existing interactions were removed.
      • CMS refined and expanded these interactions to include newly identified diagnosis pairings that consistently drive higher resource use.

    Why These Changes Matter

    Accurate and complete secondary diagnosis coding is essential for capturing all eligible PDGM adjustments. Agencies and coders should ensure that all relevant diagnoses are documented, as missing or incorrect codes can result in lost payment opportunities.

    It’s also important to review the CY 2026 comorbidity updates, since changes to the low and high adjustment lists can affect PDGM payments. Checking the updated subgroup tables will help identify which diagnoses trigger low adjustments and which combinations qualify for high comorbidity adjustments.

    Part of a Broader PDGM Recalibration

    These comorbidity updates are one component of CMS’s broader PDGM recalibration for CY 2026, which also includes changes to:

    • Case-mix weights
    • Functional impairment levels
    • Low-Utilization Payment Adjustment (LUPA) thresholds

    Together, these updates aim to improve the accuracy and fairness of Medicare home health payments by better reflecting patient complexity.

    Reference Tables Included

    For easier reference, the Low Comorbidity Adjustment Subgroups and High Comorbidity Subgroup Interaction tables can be accessed through the links below so you can quickly access them without digging through the full Final Rule document.